I was just reading "The Disappearing Spoon" and decided to see if there were any Tantalum coins. Check this out, only 3 minted. http://www.ebay.com/itm/KERGUELEN-I...3712967?pt=US_World_Coins&hash=item1c384de3c7
Well if you want an affordable tantalum coin, you can try looking for space coins from Kazakhstan. They are definitely a lot more affordable than these NCLT or even non-existing country coinage.